Tuesday, May 19, 2015

Carls Konged '78 CB750

Spent some time over at Carl's today to help get his bike back on the road. Needed lots of love after being his sole mode of transportation for a long time and then shoved in the corner for a few years like an old broom.

Just a few things off the checklist (stock k8 engine):

Set points:
Gap 0.012" to 0.016"
Static set 1-4 timing on F-mark with ohmeter
Static set 2-3 timing
Lock plate and roll.

Valve Lash:
E.O.I.C method
Intake 0.002"
Exhaust 0.003"

Set cam chain tensioner:
Push kicker to get tension on the front of the cam chain and slack on the rear. Loosen lock nut on tensioner and back out the set screw. Listen for movement in the tensioner and lock down the set screw and lock nut.

After setting the valve lash, I successfully snapped a Tappet cover off. Good word of advice: Just snug the Tappet covers down lightly. This one was fatigued or already broken because I didn't even get the gasket seated to the valve cover before it popped.

Meanwhile Carl replaced the fuel pump in his car. Lovely day.

Monday, May 18, 2015

Rock Flute Specifications:

For my own notes and for those interested, here are the specs on Rock Flute.  I'll update this as things change... because they always do. For instance, the green paint in the picture is actually a brighter green than the color code listed below.  I will update the picture as soon as the bike is repainted.

 
Engine:
10.9 to 1 CR
1978 CB750 F bottom end
1976 K model cylinders, Decked
1976 K model Head, Stage II porting, decked by Mike Reick
                33.5 mm OS intake valves, stock exhaust valves
                Megacycle 125-75 cam, 0.005” Int/Exh tappet clearance, 105 int 104.5 exh lobe centers, no adv.
                                (More cam specs in chart below)
                Adjustable cam sprocket
                HD Valve springs and titanium keepers
                Late model cam towers with unbolted early model rocker shafts
Wiseco 836 forged piston kit
CycleX Super Rods
New primary chains installed
Reinforced valve cover with cam tower stabilizers

Transmission/Final Drive:
F model transmission, backcut with close ratio 4th and 5th gear
             Primary: 1.708:1
            1st:           2.500:1
            2nd:          1.708:1
3rd:           1.333:1
            4th:           1.133:1
5th:           0.969:1
Barnett Clutch plates and springs
Drilled clutch basket with oil grooves for added oiling
Final Drive: 17/48 2.82:1

Ignition:
Dyna 2000 ignition with 3 ohm Dyna minicoils
Total Timing Advance: 35*
Timing curve: 4 (changed 6/12/15 from 5 which may be causing low/mid stumble)
Rev limiter: 10,500 RPM
NGK DR8EA 5 kohm Resistor type spark plugs @ 0.036” gap *test gap up to 0.050" for better burn, idle, and mpg (resistor plugs used to eliminate noise in digital tach and increase spark duration)

Fuel/Intake:
Ramflo Filters
Sudco VM29/CB750 Adapter boots with vacuum ports
Mikuni VM29 Smoothbore Carburetors
               Mains: 115
               Pilots: 15
               Air Jets: 1.1
Air Screws: 1.5 Turns
Needles: #5DL31 with clip @ #1
Needle Jets: 0-6 (verify)
Throttle Valves: 1.5
Float Height: 23 mm

Exhaust:
4-2, 2” long baffle with 1.25” inner diameter

Frame:
Cycle One Manufacturing rigid
2" forward
4" up
36* rake, Harley 1" neck
5" ride height
Paint: Sikkens Rally Black
 
Body:
Fuel Tank: 1969 Triumph Tiger Daytona 500
Rear Fender: 5" Ducktail ribbed fender, 7 Metal West
Paint: Gloss Black/MD State Police Green - BMB1B (ICI Autocolor paint code)
Seat: Satin black powder-coated Accufast seat pan with single leaf spring suspension
 
Suspension/Front End:
Vincent Style girder with Cannondale MTB air shocks @ 60 psi each
 
Wheels/Tires/Brakes:
Front Wheel:  Satin black powder-coated SOHC CB750 rim laced to a CL450 dual leading shoe brake hub
Front Tire:  Shinko 705 110/80-19
Rear Wheel:  Satin black powder-coated DOHC CB750 rim laced to a late model CB750 drum hub
Rear Tire:  Shinko 705 130/90-19
 
Gauges/Info Center:
Vapor Computer System
     Speedometer, Tachometer, Trip/Odometer, Top Speed, Time, Head Temperature, Shift Lights/Redline Warning
Analog Oil Pressure Gauge
 
Lighting:
Headlight:  Cycle Standard 4.5 inch early style headlight with high beam indicator
Taillight:  Bullet style dual filament

Oil:
Capacity: 5 Quarts
Mobil 1 20w-50 Full Synthetic

Fuel:
Capacity: 3.7 Gallons
Premium 91+ Octane

Curb Weight:
450 Lbs

 

Cam Specs
Valve Lift
Duration
Int. Open
Int. Close
Exh. Open
Exh. Close
Lobe Center
Overlap
tappet Clearance
Sealed Duration
Int.
Exh.
Int.
Exh.
BTC
ABC
BBC
ATC
Int.
Exh.
Calculated
Int.
Exh.
Calculated
Megacycle 125-75
0.400
0.375
262 @.04
257 @.04
26
56
53
24
105
104.5
50
0.005
0.005
251

 

Saturday, May 9, 2015

Rewelding and cleaning up some of the parts on Rock Flute

So I found out my kickstand can't take the entire weight of the bike dropping down on it. 450 lbs bent the tab enough for me to have to reweld it. While I had the welder out, I also added a bit of metal to the headlight mount because it had a tendency to vibrate at high speed. Both problems fixed and covered with a half assed attempt to blend satin black paint.

Wrap up with some ginger beer

Wednesday, May 6, 2015

Carburetor Return Springs

Brought to you by you local hardware store.